Conventional touch sensitive virtual buttons, i.e., buttons painted on a stationary flat surface and actuated by touch, are capacitance-based or resistance-based. Certain touch sensitive user input systems detect hovering objects as well. Examples include U.S. Publication No. 2008/0012835 A1 for HOVER AND TOUCH DETECTION FOR DIGITIZER and U.S. Publication No. 2006/0244733 A1 for TOUCH SENSITIVE DEVICE AND METHOD USING PRE-TOUCH INFORMATION.
Prior art hover detection systems based on reflected light determine a height of an object above a surface based on an amount of reflected light: the nearer the object—the more light is reflected onto the detector situated beneath the touch surface. Therefore, prior art systems are able to detect a hovering object over time and determine whether the object is moving closer or farther away based on relative amounts of detected light. I.e., diminishing light detection over time indicates an object moving away from the surface, and increasing light detection over time indicates an object moving toward the surface. In other words, the determined height is relative to other heights in a series of detections, but the actual height remains unknown. Indeed, different materials reflect different amounts of light, e.g., a white glove reflects more light than a black glove, and the reflective properties of a hovering object are not known by the system. Therefore, the system cannot determine the height at which the object is situated above the surface based on the amount of reflected light detected. In addition, because prior art proximity detectors require a series of detections of the object at different heights in order to rank the heights in relation to each other, a single proximity detection or a series of detections of a stationary hovering object will provide little information about the height of the object.
Graphical user interfaces (GUIs) enable interaction with visual elements displayed on a screen. When the extent of a GUI exceeds that of the screen, a user is restricted to interacting with only the portion of the GUI that is displayed on the screen. In order to activate a visual element virtually located outside of the displayed portion of the GUI, the user must pan the GUI, moving a portion of the GUI from outside of the display into the display, while displacing a currently displayed portion of the GUI out of the display. It would thus be of advantage to enable user interactions with GUI elements that are virtually located beyond the display area of the screen, without panning the GUI.